Mechanical Pipe Coupling Having Spacers

ABSTRACT

A mechanical pipe coupling is disclosed having an arcuate band with first and second ends in facing relation. A hinge is positioned between the first and second ends allowing the ends to move relatively to one another. Connection members are mounted on the ends, and a spacer is positioned between the ends to maintain the ends in spaced apart relation sufficient to allow end portions of a pipe to be inserted between arcuate surfaces which extend radially inwardly from the band. The spacer is configured to allow for tightening of the connection members to draw the ends together and permit the arcuate surfaces to engage the outer surfaces of the pipe elements and form a joint.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.11/125,430, filed May 10, 2005, which claims priority to U.S.Provisional Application No. 60/571,596, filed May 14, 2004.

FIELD OF THE INVENTION

This invention concerns mechanical pipe couplings that have segmentsmaintained in spaced apart relation using spacers.

BACKGROUND OF THE INVENTION

Mechanical couplings for joining pipe elements together end-to-endcomprise interconnectable segments that that are positionablecircumferentially surrounding the end portions of co-axially alignedpipe elements. The term “pipe element” is used herein to describe anypipe-like item or component having a pipe like form. Pipe elementsinclude pipe stock, pipe fittings such as elbows, caps and tees as wellas fluid control components such as valves, reducers, strainers,restrictors, pressure regulators and the like.

Each mechanical coupling segment comprises a housing having arcuatesurfaces which project radially inwardly from the housing and engageplain end pipe elements or circumferential grooves that extend aroundeach of the pipe elements to be joined. Engagement between the arcuatesurfaces and the pipe elements provides mechanical restraint to thejoint and ensures that the pipe elements remain coupled even under highinternal pressure and external forces. The housings define an annularchannel that receives a gasket or seal, typically an elastomeric ringwhich engages the ends of each pipe element and cooperates with thesegments to provide a fluid tight seal. The segments have connectionmembers, typically in the form of lugs which project outwardly from thehousings. The lugs are adapted to receive fasteners, such as nuts andbolts, which are adjustably tightenable to draw the segments toward oneanother.

To ensure a good fit between the couplings and the pipe elements, thearcuate surfaces on prior art couplings have a radius of curvature thatis substantially matched to the radius of curvature of the outer surfaceof the pipe element that it is intended to engage. For couplings usedwith grooved pipe elements, the radii of curvature of the arcuatesurfaces are smaller than the radii of curvature of the outer surfacesof the pipe elements outside of the grooves so that the arcuate surfacesfit within and engage the grooves properly.

This geometrical relation between the arcuate surfaces of the couplingsand the outer surfaces of the pipe elements in prior art couplingsresults in a tedious and time consuming installation process whenmechanical couplings are used. Typically, the coupling is received bythe technician with the segments bolted together and the ring sealcaptured within the segments' channels. The technician firstdisassembles the coupling by unbolting it, removes the ring seal,lubricates it (if not pre-lubricated) and places it around the ends ofthe pipe elements to be joined. Installation of the ring seal requiresthat it be lubricated and stretched to accommodate the pipe elements, anoften difficult and messy task, as the ring seal is usually stiff andthe lubrication makes manual manipulation of the seal difficult. Withthe ring seal in place on both pipe elements, the segments are thenplaced one at a time straddling the ends of the pipe elements andcapturing the ring seal against them. During placement, the segmentsengage the seal, the arcuate surfaces are aligned with the grooves whenpresent, or with alignment marks made on the outside surfaces of thepipe elements, the bolts are inserted through the lugs, the nuts arethreaded onto the bolts and tightened, drawing the coupling segmentstoward one another, compressing the seal and engaging the arcuatesurface within the grooves.

As evident from the previous description, installation of mechanicalpipe couplings according to the prior art requires that the techniciantypically handle at least seven individual piece parts (and move whenthe coupling has more than two segments), and must totally disassembleand reassemble the coupling. Significant time, effort and expense wouldbe saved if the technician could install a mechanical pipe couplingwithout first totally disassembling it and then reassembling it, pieceby piece.

SUMMARY OF THE INVENTION

The invention concerns a pipe coupling positionable straddling facingend portions of a pair of pipe elements for securing the pipe elementstogether in end-to-end relationship. The end portions of the pipeelements have an outer surface of substantially cylindrical profile. Thepipe coupling comprises a plurality of coupling segments. Each couplingsegment has a pair of arcuate surfaces adapted to interface with thecylindrically profiled outer surfaces of the pipe elements. The arcuatesurfaces are in spaced apart relation lengthwise of one another. Eachcoupling segment has connection members for adjustably connecting onecoupling segment to another.

A spacer is positioned between the coupling segments. The spacermaintains the coupling segments in predetermined spaced apart relationsufficient to allow the end portions of the pipe elements to be insertedbetween the coupling segments in end-to-end relationship. The connectionmembers are adjustably tightenable for drawing the segments together.The spacer is configured to allow for tightening of the connectionmembers to permit the arcuate surfaces to engage the outer surfaces ofthe pipe elements when the portions of the pipe elements are insertedbetween the coupling segments in end-to-end relationship.

In one embodiment, the spacer is configured to be collapsible upon theapplication of a predetermined compressive force resulting fromtightening of the connection members. Collapse of the spacer permits thearcuate surfaces to engage the outer surfaces of the pipe elements.

Preferably, the collapsible spacer comprises a tube positioned betweenthe connection members. The tube has a circular cross section and may beformed from a polymer material. Lightweight metal tubes are alsofeasible. The tube may be corrugated or scored to facilitate collapse ofthe tube upon tightening of the connection members.

In another embodiment, the spacer is configured to be removable frombetween the segments. Removal of the spacer allows for tightening of theconnection members permitting the arcuate surfaces to engage the outersurfaces of the pipe elements. The removable spacer preferably takes theform of a block-shaped body positioned between the connection members.The block-shaped body may be releasably attached to one of theconnection members.

In a particular embodiment, the arcuate surfaces on the segments subtendan angle of less than 180° and have a radius of curvature greater thanthe radius of curvature of the outer surfaces of the pipe elements. Thesegments are deformable upon adjustable tightening of the connectionmembers so as to conform the curvature of the arcuate surfaces to theouter surfaces of the pipe elements.

In another embodiment, the arcuate surfaces project radially inwardlyfrom the segments. A pair of notches is formed in each of the arcuatesurfaces proximate to each end of the segments. The notches provideclearance for insertion of the end portions of the pipe elements betweenthe segments when the segments are in the predetermined spaced apartrelationship.

In yet another embodiment, the segments are neither intentionallydeformable nor are there clearance notches present, the coupling usingthe spacers only to allow the pipe elements to be inserted between thesegments when in the spaced apart, pre-assembled configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-1B are longitudinal cross-sectional views of a deformablemechanical pipe coupling according to the invention;

FIGS. 2 and 3 are partial cross-sectional views of the pipe couplingshown in FIG. 1;

FIGS. 4 and 5 are perspective views, partially cut away, of seals usedwith pipe couplings according to the invention;

FIGS. 6-7 and 8 are axial views of various pipe coupling embodimentsaccording to the invention;

FIGS. 7A and 9-13 are longitudinal sectional views of pipe couplingembodiments according to the invention;

FIG. 14 is a perspective view of a pipe coupling according to theinvention;

FIG. 15 is a side view of the pipe coupling shown in FIG. 14;

FIG. 16 is a cross-sectional view taken at line 16-16 in FIG. 14;

FIG. 17 is an axial view, partially cut away, of pipe couplingembodiment according to the invention;

FIG. 18 is an axial view of a pipe coupling embodiment according to theinvention;

FIG. 19 is an axial view of a pipe coupling embodiment according to theinvention;

FIG. 20 is an axial view, partially cut away, of a pipe couplingembodiment according to the invention;

FIG. 21 is a partial sectional view of the pipe coupling shown in FIG.20;

FIG. 22 is an axial view, partially cut away, of a pipe couplingembodiment according to the invention;

FIG. 23 is an axial view of a pipe coupling embodiment according to theinvention; and

FIGS. 24-26 are axial views of a pipe coupling embodiments according tothe invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIGS. 1 and 2 show a pipe coupling 10 according to the invention.Coupling 10 is formed from coupling segments 12 and 14 which areinterconnectable with one another to straddle end portions 16 a and 18 aof pipe elements 16 and 18 to secure the pipe elements together inend-to-end relationship. The end portions of the pipe elements haverespective outer surfaces 20 and 22 of substantially cylindricalprofile.

Interconnection of the coupling segments 12 and 14 is effected byconnection members, preferably in the form of lugs 24 and 26 best shownin FIG. 2. The lugs are preferably positioned at each end of eachsegment and project outwardly from the segments. Lugs 24 and 26 arepositioned in facing relation to one another and adapted to receivefasteners, preferably in the form of bolts 28 and nuts 30 which areadjustably tightenable and cooperate with the lugs 24 and 26 foradjustably connecting the coupling segments to one another as discussedin further detail below.

As best shown in FIG. 1, each segment 12 and 14 comprises a pair ofarcuate surfaces 32 and 34. The arcuate surfaces are in spaced apartrelation to one another and preferably project radially inwardly towardthe pipe elements 16 and 18. The surfaces extend from a housing 36having sidewalls 38 joined to a backwall 40, the sidewalls and backwallforming a channel 42 that receives a seal 44.

Examples of seals 44 are shown in FIGS. 4 and 5. Seal 44 is preferably aflexible, resilient ring formed from elastomeric material. The seal mayhave lips 46 that use the internal pressure within the pipes to increasethe sealing force between the seal and the outer surfaces 20 and 22 ofthe pipe elements 16 and 18. As shown in FIG. 5, seal 44 may also have atongue 48 positioned between the lips 46, the tongue extendingcircumferentially around the seal and projecting radially inwardly.Tongue 48 provides a stop surface that engages the ends of pipe elements16 and 18 to ensure proper positioning of the seal 44 relatively to thepipe elements as described in detail below. Engagement of the pipeelements with tongue 48 also effects alignment of the arcuate surfaceswith the grooves (if present), or with alignment marks on the outsidesurface of the pipe elements.

As illustrated in FIG. 2, arcuate surfaces 32 and 34 have radii ofcurvature 50 greater than the radii of curvature 52 of the outersurfaces 20 and 22 of pipe elements 16 and 18. Furthermore, the arcuatesurfaces 32 subtend an angle 54 of less than 180°. Angles 54 betweenabout 40° and about 179° are practical. As a result of this arcuatesurface geometry, segments 12 and 14 may be pre-assembled separated fromone another such that pipe elements 16 and 18 may be inserted directlyinto the coupling 10 as shown in FIG. 1 without first disassembling thecoupling. This feature provides a significant advantage over prior artcouplings which must be assembled onto the pipe ends piece by piece.Joining of the pipe ends with a coupling 10 according to the inventionproceeds much more smoothly and quickly than with prior art couplingsbecause the technician handles fewer pieces and does not have to threadnuts onto bolts. In the embodiment shown in FIG. 1, the seal 44 has anouter diameter 56 sized to hold the coupling segments 12 and 14 inspaced apart relation sufficient to allow the pipe ends to be insertedas described above. The seal inner diameter 58 is sized to receive theend portions 16 a and 18 a of the pipe elements simply by pushing thecoupling over the pipe elements or by inserting the pipe elements intothe coupling. Other embodiments having different features for supportingthe segments in spaced relation are described below.

After both pipe elements 16 and 18 are inserted into coupling 10 asshown in FIG. 1A, nuts 30 are tightened (see also FIG. 2). The nuts 30cooperate with their bolts 28 to draw the arcuate surfaces 32 and 34 onsegment 12 toward those on segment 14. Tightening of the nuts exerts aforce on the lugs 24 and 26 which brings the segments into contact withthe pipe elements and causes the segments 12 and 14 to deform such thatthe radius of curvature 50 of the arcuate surfaces 32 and 34substantially conforms to the radius of curvature 52 of the pipeelements 16 and 18. This action is illustrated by comparing FIGS. 2 and3 and 1A and 1B, wherein the gap 60 between the arcuate surfaces and thepipe outer surfaces diminishes as the arcuate surfaces are brought intoengagement with the outer surfaces of the pipe ends. Deformation of thesegments 12 and 14 is preferably substantially elastic, allowing thesegments to spring back substantially to their original shape when thenuts 30 are loosened, thereby permitting the coupling 10 to be reused inthe manner according to the invention as described herein. The segmentsmay also be designed to have significant plastic deformation, whereinthe deformation imparts a permanent set to the segments. For practicalcouplings, there will generally be some degree of both plastic andelastic deformation occurring in the segments as a result of installingthe coupling on pipes and tightening the fasteners. Additionally, whenthe segments 12 and 14 are in the undeformed state (FIG. 2), the lugs 24and 26 may be angularly oriented in relation to one another. Relativeangles 62 up to about 10° are practical. As shown in FIG. 3, therelative angular orientation of the lugs 24 and 26 is reduced as thesegments are deformed, and the geometry may be designed such that thelugs are substantially parallel once the arcuate surfaces 32 and 34substantially conform to the outer surfaces 20 and 22. This is preferredbecause, when fully tightened, the bolt head and nut will be insubstantially flat contact with the lugs, thereby avoiding inducingbending moments in the bolts which can cause permanent deformation ofthe bolts. The seal 44 is also deformed by this process, as shown inFIG. 1B, with the lips 46 coming into full engagement with the pipeelement outer surfaces 20 and 22. Because the seal 44 is substantiallyincompressible, it must be provided with space into which it may expandwhen compressed by the segments. This space is provided by a concavity64 positioned in the backwall 40 between the sidewalls 38. Concavity 64may take virtually any practical shape and allows for volume change ofthe seal when it is heated or exposed to fluids, thereby distributingthe deformation of the seal more evenly over its circumference andmitigating the tendency of the seal to extrude outwardly from betweenthe segments between the lugs. The concavity also prevents tongue 48, ifpresent, from being forced between the ends of the pipe elements andimpede flow therethrough.

As shown in FIGS. 2 and 3, for the preassembled coupling 10, it isadvantageous to hold nuts 30 in a position on bolts 28 that willmaintain the segments 12 and 14 in the desired spaced apart relation asdetermined by contact between the segments and the seal 44. This isconveniently accomplished by deforming the threads 29 of bolts 28,preferably by staking. Staking the bolts hinders the rotation of thenuts and prevents them from unscrewing from the bolts under the effectof vibration, for example, during shipping, and keeps the coupling inthe preassembled state with all of its parts together prior toinstallation. The staking is readily overcome when the nuts aretightened with a wrench.

The bending stiffness of the segments may be tuned to control the amountof force necessary to deform them in order to reduce the requiredassembly torque and mitigate galling between the nut and the lug. Asshown in FIG. 6, sections of increased bending flexibility 66 may beformed in the housing 36 of the segments 12 and 14 by reducing the areamoment of inertia of the segment. This reduction is preferably achievedby adding one or more cut-outs 68 in either or both the backwall 40 andthe arcuate surfaces 32 and 34.

Alternately, as shown in FIG. 7, the segments may have arcuate surfaces32 and 34 (not shown) comprising inwardly projecting teeth 69. Teeth 69engage outer surfaces of the pipe elements to provide mechanicalrestraint, and are especially advantageous when used with plain end pipeelements. Teeth 69 may be substantially continuous, as shown on segment14, or intermittent, as shown on segment 12. Single teeth, preferablefor small couplings, are also feasible. As shown in FIG. 7A, teeth 69may also be arranged in pairs on opposite sides of the segment toincrease the mechanical restraint provided by the coupling.

Although couplings according to the invention are described above ascomprised of two segments, this is by way of example only. Couplingswith more than two segments are feasible and preferred for largerdiameter pipes due to the manufacturing costs, as reducing the size ofthe segments is economically advantageous. A further advantage is thatthe spacing between the lugs is reduced, requiring fewer turns of thenut and shorter bolts. Standard depth sockets may thereby be used duringinstallation. FIG. 8 shows an example of a coupling embodiment 72 havingfour segments 74 similar to those described above.

Couplings have thus far been shown wherein all of the arcuate surfaceshave substantially the same radius of curvature. Whereas such aconfiguration is appropriate for joining pipes having substantially thesame diameter to one another, FIG. 9 shows a coupling embodiment 76 forcoupling pipe elements of different diameters. Coupling 76 is formed oftwo segments 78 and 80 (although it may have more than two segments).Each segment has a first arcuate surface 82 having a first radius ofcurvature 84, and a second arcuate surface 86 having a second radius ofcurvature 88 smaller than the first radius of curvature 84. This allowscoupling 76 to join a pipe element 90 having a larger diameter to a pipeelement 92 having a smaller diameter. Analogous to the couplingsdescribed above, the radius of curvature 84 is greater than the radiusof curvature of the outer surface of pipe element 90, and the radius ofcurvature 88 is greater than the radius of curvature of the pipe element92. This geometric relationship allows the pipe elements 90 and 92 to beinserted into a pre-assembled coupling 76 and achieve the advantages ofthe invention. The coupling segments 78 and 80 deform upon theapplication of force by the adjustable connection members to conform theradii of curvature to the outer surface of the pipe elements when thearcuate surfaces engage the pipe elements.

In a preferred embodiment, shown in FIG. 10, the inwardly projectingarcuate surfaces 32 and 34 of coupling 10 engage grooves 94 formed inthe outer surfaces 20 and 22 of pipe element end portions 16 a and 18 a.Interaction between the arcuate surfaces 32 and 34 with their respectivegrooves 94 permits the coupling to provide relatively high end restraintto withstand forces caused by internal pressure or external loads. Toobtain higher end restraint, it is found useful to add a second set ofarcuate surfaces that interact with a second set of grooves in the pipeelements. This embodiment is illustrated in FIG. 11, wherein a coupling96 is comprised of segments 98 and 100, each segment having two pairs ofarcuate surfaces 102 and 104 that project inwardly from the segments.The arcuate surface pairs are in substantially parallel, spaced relationto one another and engage pairs of grooves 106 in the surfaces of thepipe elements 108 and 110 which they connect together.

In another embodiment, shown in FIG. 12, couplings according to theinvention such as 10 may be used with pipe elements 112 and 114 havingraised circumferential shoulders 116 that are engaged by the arcuatesurfaces 32 and 34 of the segments 12 and 14. Alternately, as shown inFIG. 13, a coupling 118 according to the invention having segments 120and 122 with respective arcuate surfaces 124 and 126 is used with pipeelements 128 and 130 having flared end portions 132 and 134. Note thatin the example embodiments shown in FIGS. 9-13, the seal 44 has thetongue 48 which is effectively used to position the pipe ends within thecoupling upon insertion, the tongue acting as a pipe stop to aid inlocating the pipe ends at the proper depth within the couplings.

Another coupling embodiment 136 is shown in FIG. 14. Coupling 136 iscomprised of two segments 138 and 140 from which lugs 142 and 144extend, the lugs cooperating with fasteners 146 to act as connectionmembers for adjustably connecting one coupling segment to another. Asdescribed above, each segment has a pair of arcuate surfaces 148, 150,each preferably projecting radially inwardly from the segments. Thearcuate surfaces subtend an angle 152 less than 180° and have a radiusof curvature 154 greater than the radius of curvature of the pipeelements which the coupling is to join together. Anti-rotation teeth 70are positioned adjacent to the arcuate surfaces and project radiallyinwardly to engage the pipe elements and provide additional torsionalrigidity.

As best shown in FIG. 14, each segment 138 and 140 has a pair ofangularly oriented surface portions 156 and 158 located adjacent to eachof the lugs 142 and 144. As illustrated, the slope of surface portion156 may be opposite to the slope of surface portion 158 on each segment.(Both surfaces could also be sloped in the same direction as well.) Thisopposite slope relationship between the surfaces on a segment results insurfaces having compatible slopes being positioned in facing relation ina pre-assembled coupling as shown in FIG. 15. When the fasteners 146 aretightened, conforming the arcuate surfaces to the outer surfaces of thepipe elements, the angular surface portions 156 and 158 on each segmentengage and slide relatively to one another, causing the segments to drawtogether and rotate relatively to one another in opposite directionsabout an axis 160 oriented substantially perpendicularly to the axis ofthe pipe elements being joined. These motions of the segments 138 and140 causes the arcuate surfaces 148 and 150 to engage grooves in thepipe elements and adds rigidity to all axes of the joint as previouslydescribed. For coupling segments having surface portions with the sameslopes, the couplings move along the pipe in opposite directionsrelatively to one another with similar effect.

As shown in cross section in FIG. 16, the segments 138 and 140 formingthe coupling 136 have a channel 162 defined by a housing 164. Thehousing is formed from a back wall 166 and sidewalls 168, and receives aseal 170 which is sized to position the segments 138 and 140 in spacedapart relation so as to allow insertion of pipe elements into thepre-assembled coupling shown in FIG. 14. A concavity 172 is provided inthe back wall to provide a space for volume change of the seal when itis heated or exposed to fluids as well as to prevent tongue 48 frombeing forced between the ends of the pipe elements and impede flowtherethrough due to compression of the seal.

In another coupling embodiment, shown in FIG. 17, the coupling 174 againis comprised of at least two coupling segments 176 and 178, each havinginwardly projecting arcuate surfaces 180 as described above. However,arcuate surfaces 180 have notches 182 and 184 positioned at oppositeends. The notches 182 and 184 provide clearance at the 3 o'clock and 9o'clock positions of the coupling where it is most needed to permit pipeelements to be inserted into the pre-assembled coupling 174. Theavailability of increased clearance at these locations allows thecoupling segments 176 and 178 to be spaced closer to one another in thepre-assembled configuration than would be the case if the clearance wasnot available at the ends of the surfaces. By having the segments of thepreassembled coupling closer together, the amount of deformationrequired to conform the arcuate surfaces to the pipe element outersurface is reduced and thereby by energy required to tighten thefasteners.

Another coupling embodiment 192 according to the invention is shown inFIG. 18. Coupling 192 comprises an arcuate band 194 surrounding acentral space 196. Band 194 has opposite ends 198 and 200 positioned infacing relation to one another. Ends 198 and 200 are in spaced relationin the pre-assembled coupling and have connection members mountedthereon, preferably in the form of projecting lugs 202 and 204 adaptedto receive a fastener such as bolt 206 and nut 208. The bolt and nutcooperate with the lugs to deform the band 194 and bring the ends 198and 200 toward one another after pipe elements have been inserted intothe central space 196 for coupling in end-to-end relationship. Band 194has a pair of arcuate surfaces 210, only one of which is visible in thefigure. The arcuate surfaces are in spaced relation lengthwise of oneanother as illustrated in FIG. 10 and described above for otherembodiments. The arcuate surfaces 210 have a greater radius of curvaturethan the outer surface of the pipe ends that the coupling is to jointogether. This geometric configuration, and the separation of the ends198 and 200 allows the pipe elements to be inserted into central space196. Upon tightening of the nut 208 the band 194 is deformed such thatthe radius of curvature of the arcuate surfaces 210 are forced toconform with the radius of curvature of the outside surface of the pipeelements which they engage. Note that in the preassembled state,projecting lugs 202 and 204 are preferably angularly oriented withrespect to one another, having a relative angle 212 up to about 20°.Tightening of the fastener draws the lugs toward each other, and resultsin decreasing the relative angle 212, preferably to the point whereinthe lugs are substantially parallel to one another. This is particularlyadvantageous for a flexible coupling which does not depend upon the pipeelements to form a reaction point to cause the deformation incombination with the bolts, the friction incurred at the reaction pointsinhibiting flexibility.

Coupling 192 includes a seal 214 positioned within the band 194 betweenthe arcuate surfaces 210. Seal 214 may be similar to those illustratedin FIGS. 4 and 5 and sized to receive the pipe elements for creating afluid tight seal when the band is deformed.

The bending flexibility of coupling 192 may be adjusted by reducing thearea moment of inertia of band 194. Such adjustments may be effected bypositioning cut-outs 216 in the band. Alternately, as shown in FIG. 19,a hinge 218 may be provided between the ends 198 and 200. Hinge 218 ispreferably positioned equidistant from the ends of the band and providesinfinite bending flexibility, reducing the torque needed on the fastenerto draw the ends 198 and 200 toward one another. The band 194 will stilldeform as the arcuate surfaces 210 engage the outer surfaces of pipeelements to conform the radii of the surfaces with that of the pipeelement outer surfaces. When the hinge is present, the seal 214 is sizedso as to maintain the lugs 202 and 204 in spaced relation so that pipeelements may be inserted. For both the hinged and hingeless versions ofthe coupling described above, the arcuate surfaces preferably projectradially inwardly from the band and may have different radii ofcurvature from each other, as illustrated in FIG. 9, to allow thecoupling 192 to be used to join pipes having different diameters.

FIG. 20 illustrates a pre-assembled coupling 220 that does not depend onthe seal 222 to maintain its segments 224 and 226 in spaced apartrelation and ready to receive pipe elements such as 228. Coupling 220has spacers 230 that extend between segments 224 and 226 and maintainthe segments in spaced apart relation. In this example embodiment, thespacers 230 comprise collapsible tubes 232 that are positioned betweenfacing lugs 234 and 236 that extend from the segments. Tubes 232 arepreferably thin walled and circular in cross section and are arrangedcoaxially surrounding the fasteners 238. The tubes may be made oflightweight metal or a polymer material such as polypropylene and mayhave score lines 240 in their surface to create weakened regions thatfacilitate collapse of the tube under compressive loads applied by thefasteners 238. Other materials, such as cardboard and rubber are alsofeasible. The tubes are designed to be strong enough to support thesegments in spaced relation during shipping, handling and installation,but collapse at a predetermined compressive load that a technician mayapply, preferably by manually tightening the fasteners with a wrench.

In use, pipe elements to be joined end-to-end are inserted between thesegments 224 and 226. Fasteners 238 are then tightened to draw thesegments toward each other and into engagement with the pipe elements.Tightening of the fasteners places the tubes 232 under a compressiveload, and the tubes buckle and collapse as shown in FIG. 21 when thepredetermined load is achieved to allow the segments to move toward oneanother and engage the pipe elements to effect the joint.

Spacers positioned between the segments may be used with any type ofmechanical coupling. Note that in FIGS. 20 and 21, the segments 224 and226 have arcuate surfaces 242 with a radius of curvature that issubstantially the same as the radius of curvature of the outer surfaceof pipe element 228 which they are designed to engage. To provideclearance between the pipe element 228 and the segments allowing thepipe element to be inserted into the coupling while still maintaining areasonable fastener length, notches 244 and 246 are positioned atopposite ends of the arcuate surfaces 242 as best shown in FIG. 20. Thenotches provide clearance at the 3 o'clock and 9 o'clock positions ofthe coupling to permit pipe elements to be inserted into thepre-assembled coupling 220.

FIG. 22 illustrates another coupling embodiment 254 having spacers 230between segments 256 and 258 comprising the coupling. In this example,the spacers 230 comprise tubes 260 again positioned coaxially withfasteners 262 and between facing lugs 264 and 266 projecting from thesegments. Tubes 260 have corrugations 268 which facilitate theircollapse when compressive load is applied by tightening the fasteners.Note that the segments 256 and 258 are similar to those described abovewith respect to FIGS. 1 and 2, wherein the arcuate surfaces of thesegments have a greater radius of curvature than the pipe elements.

Another example of a spacer for maintaining coupling segments in spacedrelation is shown in FIG. 23. Coupling 270 is comprised of segments 272and 274 having outwardly projecting lugs 266 and 264 positioned infacing relation when the coupling is pre-assembled. The segments areheld together by fasteners 280 extending between the lugs. Spacers 282,preferably in the form of block-shaped bodies 284, are positionedbetween the lugs 266 and 264. The bodies 284 are removable from betweenthe lugs to allow the fasteners to be tightened and draw the segmentsinto engagement with pipe elements being joined.

Bodies 284 may be releasably attached to the segments, for example, heldby friction between the lugs 266 and 264. Flexible, resilient materialsare particularly advantageous for forming the bodies because bodies madefrom such materials provide adequate strength and stiffness to maintainthe couplings in spaced apart relation during rough handling but may bereadily deformed for easy removal as required. If polymer materials areused to form the bodies they may be adhered to the lugs by heat fusingor by adhesives which afford a releasable bond between the bodies andthe segments.

FIG. 24 illustrates a non-deformable coupling embodiment 286 that usesspacers 288 to maintain coupling segments 290 and 292 in spaced apartrelation so that pipe elements may be inserted between them in thepreassembled state shown. Coupling 286 has no notches or other featuresthat provide clearance facilitating inserting pipe elements intoend-to-end relation between the segments, but relies on the spacers toprovide sufficient separation for adequate clearance. The spacers 288may be similar to any described herein.

Spacers according to the invention may also be used with various othertypes of couplings. As shown in FIG. 19, a spacer 288 may be used withthe hinged coupling embodiment 192 to keep the lugs 202 and 204 inspaced apart relation so that pipe elements may be inserted. Although atubular spacer is illustrated, it is understood that any of the spacersdescribed herein are feasible for use with this coupling.

FIG. 25 illustrates an adapter coupling 294 for joining flanged pipe tonon-flanged pipe, for example, grooved or plain end. Coupling 294comprises coupling segments 296 and 298, each of which has a radiallyextending flange 300 on one side and a arcuate surface 302 on theopposite side. Segments 296 and 298 are held in spaced apart relation byspacers 304, which may comprise a collapsible tubular spacer 306 or aremovable spacer 308, or other types of spacers described herein.

FIG. 26 illustrates further types of spacer embodiments 310 feasible formaintaining coupling segments 312 and 314 in spaced apart relation.Spacers 310 comprise spring elements which deform, preferablysubstantially elastically, when subjected to a compression force by thefasteners 316. Spring elements may take any of a number of forms, forexample, an elastic rubber cylinder 318 or a coil spring 320. The use ofspring elements for spacers allows for fine control of the forcesrequired to draw the segments toward one another and also facilitatesthe reuse of the couplings without the need for substantial disassemblyas taught herein when the deformation of the spring elements issubstantially elastic.

It is anticipated that couplings having spacers as described herein mayalso include features such as the tongue and recess disclosed in U.S.Pat. Nos. 6,170,884 and 6,302,450; outlets incorporated within a segmentas disclosed in U.S. Pat. No. 3,362,730; plain end couplings that do notuse grooves as disclosed in U.S. Pat. Nos. 2,439,979, 3,024,046,5,911,446 and 6,302,450, all of these patents being hereby incorporatedby reference herein.

Mechanical pipe couplings using spacers according to the inventionprovide for rapid and sure installation creating a pipe joint whileavoiding the need to partially or totally disassemble and thenreassemble the coupling and handle the individual piece parts.

1. A pipe coupling positionable surrounding facing end portions of apair of pipe elements for securing said pipe elements together inend-to-end relationship, said end portions of said pipe elements havingan outer surface of substantially cylindrical profile, said couplingcomprising: an arcuate band having first and second ends insubstantially facing relation, said band surrounding a central space; ahinge positioned between said first and second ends, said hinge allowingsaid first and second ends to move relatively to one another; connectionmembers mounted on said first and second ends, said connection membersbeing adjustably tightenable for drawing said first and second endstoward one another; first and second arcuate surfaces mounted lengthwisealong said band on a side thereof, said arcuate surfaces being in spacedrelation alongside one another and projecting substantially radiallyinwardly into said central space; a spacer positioned between said firstand second ends of said band, said spacer for maintaining said first andsecond ends in a predetermined spaced apart relation sufficient to allowsaid end portions of said pipe elements to be inserted between saidarcuate surfaces in said end-to-end relationship; and wherein saidspacer being configured to allow for tightening of said connectionmember to permit said arcuate surfaces to engage said outer surfaces ofsaid pipe elements when said pipe elements are inserted within saidcentral space.
 2. A pipe coupling according to claim 1, wherein saidspacer is configured to be collapsible upon application of apredetermined compressive force resulting from tightening of saidconnection member, collapse of said spacer permitting said arcuatesurfaces to engage said outer surfaces of said pipe elements.
 3. A pipecoupling according to claim 1, wherein said spacer is configured to beremovable from between said ends of said band, removal of said spacerallowing for tightening of said connection members permitting saidarcuate surfaces to engage said outer surfaces of said pipe elements. 4.A pipe coupling according to claim 1, wherein said spacer comprises aspring element, said spring element being deformable upon tightening ofsaid connection member, deforming of said spacer permitting said arcuatesurfaces to engage said outer surfaces of said pipe elements.
 5. A pipecoupling positionable straddling facing end portions of a pair of pipeelements for securing said pipe elements to one another in end-to-endrelation, wherein said end portion of one of said pipe elements has anouter surface of substantially cylindrical profile and said other pipeelement has an end flange mounted thereon, said coupling comprising: aplurality of coupling segments, each of said coupling segments having aarcuate surface adapted to interface with the outer surface of said onepipe element, a flange being mounted on each of said coupling segmentsin spaced apart relation to said arcuate surface, said flange extendingradially outwardly and being engagable with said end flange of saidother pipe element; each of said coupling segments further havingconnection members for adjustably connecting one coupling segment toanother, said connection members being adjustably tightenable fordrawing said arcuate surfaces of said segments into engagement with theouter surface of said one pipe element and said flanges into alignmentwith said end flange; a spacer positioned between two of said couplingsegments, said spacer for maintaining said arcuate surfaces in apredetermined spaced apart relation sufficient to allow said one pipeelement to be inserted between said coupling segments; and wherein saidspacer is configured to allow for tightening of said connection memberto permit said arcuate surfaces to engage said outer surface of said onepipe element and said flanges to align with said end flange to effectconnection of said pipe elements in said end-to-end relationship.
 6. Apipe coupling according to claim 5, wherein said spacer is configured tobe collapsible upon application of a predetermined compressive forceresulting from tightening of said connection member, collapse of saidspacer permitting said arcuate surfaces to engage said outer surfaces ofsaid one pipe element and said flanges to align with said end flange ofsaid other pipe element.
 7. A pipe coupling according to claim 5,wherein said spacer is configured to be removable from between saidsegments, removal of said spacer allowing for tightening of saidconnection members permitting said arcuate surfaces to engage said outersurfaces of said one pipe element and said flanges to align with saidend flange of said other pipe element.
 8. A pipe coupling according toclaim 5, wherein said spacer comprises a spring element, said springelement being deformable upon tightening of said connection member,deforming of said spacer permitting said arcuate surfaces to engage saidouter surfaces of said one pipe element and said flanges to align withsaid end flange of said other pipe element.